Metallurgical lime as "a flux" ultrafine lime flour mill steelmaking, its importance has gradually get people's attention and cognition. It not only affects the steel smelting process superfine how much money one ton of lime, but also directly affect the final quality of the molten steel. The international community has been widely used good quality, fast response, slagging thorough quality "lime" instead of past use of the "ordinary lime" ultrafine lime powder, laid the foundation for high-quality steel smelting. Characteristics of the active lime: active and lively lime is a chemical properties, reaction ability, in the process of steelmaking slag melting fast speed, including S, P less harmful elements such as quality of soft-burnt lime. Quality of the merits of its main uses "the degree of activity," the indicators. The degree of activity reflects the lime in the slag and other materials response capability.